1. Field of the Invention
The invention concerns apparatus for the collection, separation and isolation of blood and more particularly concerns apparatus for the centrifugal separation of blood into its component liquid and solid portions.
2. Brief Description of the Prior Art
Advances in modern analytical instrumentation have made it possible to carry out a variety of hematological, chemical and toxicological diagnostic procedures on very small quantities of blood. This is an advantageous advance since it obviates the need to withdraw venous blood from a patient. Instead, sufficient quantities of blood may now be obtained by the less traumatic procedure of collecting capillary source blood from a finger tip, ear lobe, and the like.
Prior to my invention, the most widely used means for collecting capillary blood has been by employment of the standard capillary tube. However, collection of blood specimens in capillary tubes requires a fair degree of technical proficiency on the part of medical personnel if air pockets within the capillary collector are to be avoided. Furthermore, capillary tubes are relatively fragile and subject to ready breakage. For the storage of relatively large quantities of blood, several capillary tubes must be employed. In addition, capillary tubes are not generally suitable vessels for the blood if it is to be separated into its serum and solids components while therein. Further, blood stored therein is often difficult to remove since the blood will often clot and clog the capillary even if treated with an anti-coagulant.
Although the need for an improved apparatus for the collection, separation and isolation of capillary blood has been evident for a number of years, there have been few attempts to satisfy this need.
Prior to this invention, apparatus for the collection of capillary blood was known; see for example copending application Ser. No. 400,882 filed Sept. 26, 1973. However, such apparatus functions to collect and separate capillary blood into its component serum or plasma and solids portions only. It cannot function to effect a sealed isolation of the blood components from each other.
U.S. Pat. Nos. 3,780,935 and 3,852,194 disclose methods and apparatus for the sealed isolation of blood plasma or serum from the solid constituents of blood, by centrifugal force emplacement of a thixotrope sealant barrier between the centrifugally separated blood components. However, the apparatus of these latter disclosures have not been found satisfactory for use in the collection, separation and isolation of serum or plasma from capillary blood because they are not suitable for use with relatively small volumes of blood.
In general, the collection, separation and isolation of serum or plasma from capillary blood has posed problems not associated with the collection, separation and isolation of blood obtained from mammalian venous and arterial sources. For example, the prior art devices are generally inadequate for protecting very small volumes of capillary blood from contamination by airborne contaminants and from loss of gaseous materials normally dissolved in blood serum or plasma, between collection of the blood and its processing to isolate the serum or plasma.
The apparatus of my invention fulfills the needs of the art and provides a means for the efficient collection, separation and isolation of serum or plasma from capillary blood while protecting the isolate from exposure to contaminants or loss of gases normally dissolved in the serum or plasma.